The preparation of silk fibroin-based hydrogels and their applications in cartilage repair

With the social development, the number of patients with osteoarthritis (OA) is increasing year by year, making it crucial to explore novel therapies and treatments to facilitate cartilage repair. Among these, hydrogels have become a center of conversation as potential cartilage substitutes in view of their swelling capacity, mechanical properties, lubricating performance, and other characteristics similar with that of extracellular matrix of articular cartilage. Therefore, it is of important values to generate multi-functional hydrogels with various bioactive materials for cartilage repair. As a natural fibrous protein known for its wonderful biocompatibility, degradability, as well as mechanical strength, silk fibroin (SF) with collagen-like structure has been widely applied in cartilage repair. Therefore, utilizing SF to construct hydrogels through various crosslinking methods shows greater application potential in cartilage repair and the treatment of OA. Besides having the benefits of both SF and hydrogels, the resulting SF-based hydrogels can further load various drugs, growth factors, stem cells, etc., so as to effectively promote cartilage repair. This review summarized the construction methods of SF-based hydrogels and the research progress in cartilage repair. The future development for SF-based hydrogels in cartilage repair was also discussed, which lay the foundation for further treatment of OA.